Lithium ion batteries are among the most effective energy storage systems. They have been used in many electronic devices and are expected to play prominent roles in the next generation hybrid and plug-in-hybrid electric vehicles. Essential to the performance of these batteries are active electrode materials capable of reversibly exchanging lithium ions, especially positive electrode materials. LiMn1-xFexPO4 (0≦x≦1) particles are promising cathode materials that offer high energy density and high power density. See Padhi et al., Journal of the Electrochemical Society, 144, 1188-94 (1997); Saravanan et al., Energy & Environmental Science, 3, 457-64 (2010); and Drezen et al., Journal of Power Sources, 174, 949-53 (2007).
The performance of LiMn1-xFexPO4 particles is largely affected by their conductivities and their sizes. See Drezen et al., Journal of Power Sources, 174, (2), 949-953 (2007); and Doan et al., Advanced Powder Technology, 21, 187-96 (2010). Several processes have been developed to prepare LiMn1-xFexPO4 particles. For example, solid state reactions/ball milling processes have been used to prepare LiMn1-xFexPO4 particles in reasonable yields. See Martha et al., Angewandte Chemie International Edition, 48, 8559-63 (2009). However, these reactions consume a significant amount of energy due to their long calcination time and high calcination temperature, making them uneconomical in mass production.
There is a need to develop a process that is suitable for mass production of efficient LiMn1-xFexPO4 materials, in particular, mesoporous nano-composite particles.